July 29, 2005

Jellyfish Gone With the Wind in California

LOS ANGELES -- They came, they stung, they left. Tens of thousands of purplish-black jellyfish that invaded Orange County beaches for the past week mostly disappeared by Thursday along with a red tide of microscopic plankton on which they may have been feeding.

"The jellyfish blew away yesterday," said fire Capt. Jim Turner in Newport Beach, down the coast from Los Angeles. "The red tide has diminished tremendously, just a few streaks offshore. The water's looking blue-green and lovely. It's gorgeous."

But a renewed wind could blow them back to shore "like Mary Poppins," Turner said.

In fact, the jellyfish aren't really gone; they're heading north. Researchers say there even have been a few recent reports of a jellyfish matching the description appearing in British Columbia.

"They're drifting up coast," said Dennis Kelly, head of the Marine Science Department at Orange Coast College in Costa Mesa.

"They could come ashore again in Santa Monica Bay or even Ventura in a couple of days. There are literally hundreds of thousands of them out there," he said. "They're basically drifters. They go wherever the current takes them."

The species is called the giant black jellyfish, and Kelly said it can grow to have a 3-foot-wide canopy and tentacles up to 12 feet long.

The species was only identified about a decade ago by researchers in San Diego County and they never have appeared in such profusion, Kelly said.

A few jellyfish were spotted in La Jolla in San Diego County a month ago, vanished, were later spotted 40 miles up the coast, and then appeared in profusion in Newport and Huntington beaches last week, Kelly said.

Researchers have been taking advantage of the invasion to capture and study the jellyfish, about which little is known.

"This is probably a once-in-a-lifetime-like-thing," he said. "I've been doing marine science for 30 years and this has never happened before, not in these numbers."

The population explosion may be due to a combination of factors, Kelly said. The temperature apparently is perfect for the jellyfish and they may be feasting on a type of plankton that, in turn, feeds on the microscopic plankton of the red tide.

The tide itself has lasted for five months now, compared to the usual seasonal bloom of about a month. Kelly said the phytoplankton causing the discoloration may have been feeding off of sewage dumped into the ocean and on nutrients from urban runoff.

"We've had horrendous runoff this year because of the tremendous rainfall," Kelly said.

Other species of jellyfish are common along Southern California's coast. Turner said invasions occur periodically, and he can remember, in the 1970s, people standing in line to be treated for stings.

However, some lifeguards said they had never seen as many jellyfish.

"I've never seen that many jellyfish in my 30 years of lifeguarding and 40 years of growing up around the beach. And I've never really seen that," said Newport Beach lifeguard Capt. Eric Bauer. "We treated hundreds of stings. At one point in time, there were miles of beach with no one in the water. They were so numerous that people couldn't avoid them."